scholarly journals The Method of High Accuracy Calculation of Robot Trajectory for the Complex Curves

2020 ◽  
Vol 28 (4) ◽  
pp. 247-252
Author(s):  
Alexander Lozhkin ◽  
Pavol Bozek ◽  
Konstantin Maiorov
Keyword(s):  
Calculation Method ◽  
Geometric Modeling ◽  
Classical Method ◽  
Geometric Model ◽  
New Method ◽  
Approximation Methods ◽  
Linear Transformations ◽  
Design Quality ◽  
Complex Curves ◽  
Internal Properties

AbstractThe geometric model accuracy is crucial for product design. More complex surfaces are represented by the approximation methods. On the contrary, the approximation methods reduce the design quality. A new alternative calculation method is proposed. The new method can calculate both conical sections and more complex curves. The researcher is able to get an analytical solution and not a sequence of points with the destruction of the object semantics. The new method is based on permutation and other symmetries and should have an origin in the internal properties of the space. The classical method consists of finding transformation parameters for symmetrical conic profiles, however a new procedure for parameters of linear transformations determination was acquired by another method. The main steps of the new method are theoretically presented in the paper. Since a double result is obtained in most stages, the new calculation method is easy to verify. Geometric modeling in the AutoCAD environment is shown briefly. The new calculation method can be used for most complex curves and linear transformations. Theoretical and practical researches are required additionally.

scholarly journals Normal approximations of regular curves and surfaces

Filomat ◽  
2015 ◽  
Vol 29 (3) ◽  
pp. 457-464 ◽  
Author(s):  
Alfonso Carriazo ◽  
Carmen Márquez ◽  
Hassan Ugail
Keyword(s):  
Geometric Modeling ◽  
New Method ◽  
Curves And Surfaces ◽  
Normal Approximations

B?zier curves and surfaces are two very useful tools in Geometric Modeling, with many applications. In this paper, we will offer a new method to provide approximations of regular curves and surfaces by B?zier ones, with the corresponding examples.

scholarly journals MODELING ARCHITECTURAL FORM SURFACE DEPENDENT SECTIONS

2021 ◽  
pp. 53-58
Author(s):  
A. A. Chekalin ◽  
M. K. Reshetnikov ◽  
V. V. Shpilev ◽  
S. V. Borodulina ◽  
S. A. Ryazanov
Keyword(s):  
Geometric Modeling ◽  
Geometric Model ◽  
Residential Building ◽  
Cubic Splines ◽  
Piecewise Smooth ◽  
Additional Parameter ◽  
Mathematical Apparatus ◽  
Surface Design ◽  
Fourth Degree ◽  
Architectural Form

For the design of surfaces in architecture, as a rule, universal techniques developed for other technical industries are used. First of all, these are general kinematic surfaces and interpolation cubic splines for modeling complex piecewise smooth surfaces. The authors propose to use the fourth degree inerodifferential spline developed by them for problems of geometric modeling of architectural forms. For calculations and constructions on a computer, the proposed spline is not much more complicated than traditional cubic splines, since it has one additional parameter - a coefficient. However, this allows you to locally control the shape of a curve or surface during design, that is, to change the shape in individual areas without affecting other areas. The article proposes a method for constructing a geometric model of the kinematic surface of dependent sections with a fourth degree parabola as a generator. When using cubic splines as a guide, the surface is a 3 × 4 non-uniform (heterogeneous) spline. The article shows that the surface on the basis of the proposed mathematical apparatus can be composite piecewise-smooth. A particular case of surface design is considered on the example of creating a model of the surface of the facade of a residential building according to the existing concept. The algorithm can be easily programmed and added as a tool to existing CAD systems.

BIOMECHANICAL MODEL PREDICTING VALUES OF MUSCLE FORCES IN THE SHOULDER GIRDLE DURING ARM ELEVATION

2010 ◽  
Vol 10 (04) ◽  
pp. 643-666 ◽  
Author(s):  
ERIC BERTHONNAUD ◽  
MELISSA MORROW ◽  
GUILLAUME HERZBERG ◽  
KAI-NAN AN ◽  
JOANNES DIMNET
Keyword(s):  
Geometric Modeling ◽  
Geometric Model ◽  
Contractile Element ◽  
Muscle Forces ◽  
Active Muscle ◽  
Cross Sectional ◽  
Shoulder Complex ◽  
Arm Elevation

A three-dimensional (3D) geometric model for predicting muscle forces in the shoulder complex is proposed. The model was applied throughout the range of arm elevation in the scapular plan. In vitro testing has been performed on 13 cadaveric shoulders. The objectives were to determine homogeneous values of physiological parameters of shoulder muscles and to locate sites of muscular attachment to any bone of the shoulder complex. Muscular fiber lengths, lengths of contractile element (CE), and muscle volumes were measured, corresponding physiological cross-sectional area (PCSA) were calculated, and force/length muscle relations were found. An in vivo biplanar radiography was performed on five volunteers. The photogrammetric reconstruction of bone axes and landmarks were coupled with a geometric modeling of bones and muscle sites of attachment. Muscular paths were drawn and changes in lengths during movement have been estimated. Directions of muscle forces are the same as that of muscular path at the point of attachment to bone. Magnitudes of muscular forces were found from muscle lengths coupled with force/length relations. Passive forces were directly determined contrary to active muscle forces. A resulting active muscle force is calculated from balancing weight and passive forces at each articular center. Active muscle forces were calculated by distributing the resulting force among active muscles based on the muscular PCSA values.

scholarly journals Geometric modeling of surfaces dependent cross sections in the tasks of spinning and laying

2019 ◽  
Vol 110 ◽  
pp. 01057
Author(s):  
Yuri Deniskin ◽  
Pavel Miroshnichenko ◽  
Andrew Smolyaninov
Keyword(s):  
Composite Materials ◽  
Cross Sections ◽  
Geometric Modeling ◽  
Geometric Model ◽  
Solid Modeling ◽  
Uniform Method ◽  
Calculation Methods ◽  
Related Process

The article is devoted to the development of a geometric model of surfaces of dependent sections to solve the problems of winding by continuous fibers in the direction of the force and its related process of automated winding of composite materials. A uniform method for specifying the surfaces of dependent sections with a curvilinear generator and a method for solid modeling of the shell obtained by winding or calculation methods are described.

scholarly journals Multiphysics Modeling of Gas Turbine Based on CADSS Technology

2020 ◽  
Vol 2020 ◽  
pp. 1-21
Author(s):  
Tian Wang ◽  
Ping Xi ◽  
Bifu Hu
Keyword(s):  
Simulation Model ◽  
Domain Knowledge ◽  
Optimization Design ◽  
Geometric Model ◽  
Domain Model ◽  
Design Quality ◽  
Multiphysics Simulation ◽  
Software Technology ◽  
Domain Models ◽  
Functional Features

Product modeling has been applied in product engineering with success for geometric representation. With the application of multidisciplinary analysis, application-driven models need specific knowledge and time-consuming adjustment work based on the geometric model. This paper proposes a novel modeling technology named computer-aided design-supporting-simulation (CADSS) to generate multiphysics domain models to support multidisciplinary design optimization processes. Multiphysics model representation was analyzed to verify gaps among different domain models’ parameters. Therefore, multiphysics domain model architecture was integrated by optimization model, design model, and simulation model in consideration of domain model’s parameters. Besides, CADSS uses requirement space, domain knowledge, and software technology to describe the multidisciplinary model’s parameters and its transition. Depending on the domain requirements, the CADSS system extracts the required knowledge by decomposing product functions and then embeds the domain knowledge into functional features using software technology. This research aims to effectively complete the design cycle and improve the design quality by providing a consistent and concurrent modeling environment to generate an adaptable model for multiphysics simulation. This system is demonstrated by modeling turbine blade design with multiphysics simulations including computational fluid dynamics (CFD), conjugate heat transfer (CHT), and finite element analysis (FEA). Moreover, the blade multiphysics simulation model is validated by the optimization design of the film hole. The results show that the high-fidelity multiphysics simulation model generated through CADSS can be adapted to subsequent simulations.

scholarly journals High-precision Joint 2D Traveltime Calculation for Seismic Processing

2018 ◽  
Vol 22 (4) ◽  
pp. 327-334 ◽  
Author(s):  
Hui Sun ◽  
Fanchang Meng ◽  
Zhihou Zhang ◽  
Cheng Gao ◽  
Mingchen Liu
Keyword(s):  
High Precision ◽  
Calculation Method ◽  
Numerical Models ◽  
New Method ◽  
Fast Marching Method ◽  
Surrounding Area ◽  
Fast Marching ◽  
Seismic Processing ◽  
Grid Nodes ◽  
Marching Method

Fast Marching Method (FMM) boasts high calculation efficiency and strong adaptability and stability while being applied to seismic traveltime. However, when it is applied to the largescale model, the calculation precision of FMM is insufficient. FMM has poor calculation precision near the source, which is an essential reason for the low accuracy of the whole algorithm. This paper puts forward a joint traveltime calculation method to address the problem. Wavefront Construction (WFC) with a relatively high calculation accuracy rather than FMM is adopted for calculation of the grid nodes’ traveltime near the source. After that, FMM is used to calculate the seismic traveltime in the remaining area. Joint traveltime calculation method greatly improves the calculation accuracy of the source’s surrounding area and the calculation accuracy of FMM. According to the new method, FMM is still adopted for the calculation of most grid nodes in the model, so the high calculation efficiency of FMM is maintained. Multiple numerical models are utilized to verify the above conclusions in the paper. 

The Study on the Linking-Up of Free-Form Surface Fiber Placement Track Based on Mesh Creating

2008 ◽  
Vol 392-394 ◽  
pp. 682-687 ◽  
Author(s):  
Zhong Xi Shao ◽  
Hong Ya Fu ◽  
De Cai Li
Keyword(s):  
Projective Plane ◽  
Calculation Method ◽  
New Method ◽  
Free Form ◽  
Parallel Projection ◽  
Reference Vector ◽  
Fiber Placement ◽  
Vertex Point ◽  
Free Form Surface ◽  
Pass Through

When using meshing creating method of FP (fiber placement) track, once the track point falls at some vertex point of mesh element, in the meantime the vertex point happens to be shared by several mesh elements, there needs a reasonable calculation method to select next mesh element which the FP track will pass through. Then it comes to the problem on linking of FP tracks. In order to solve it, in this paper, the author puts forward a new method, in which parallel projection theory is used, project need analytical mesh element and FP reference vector to a sound projective plane, on which the mesh element be selected and the FP track be calculated, then the FP track would be projected back to the placement surface. Program using this method realized a reasonable joint at the shared vertex point of meshing elements, which the FP direction has little change, and the mutation of track doesn’t come forth. So, the correctness of the method, which putted forward in this paper, is proved.

Research on the Vehicle Effects of the Assembled Bridge by Influence Surface

2014 ◽  
Vol 889-890 ◽  
pp. 1410-1413
Author(s):  
Dong Liang ◽  
Zi Shuo Li ◽  
Hui Cai Shen
Keyword(s):  
Distribution Coefficient ◽  
Calculation Method ◽  
New Method ◽  
Accurate Calculation ◽  
Transverse Distribution ◽  
Bridge Safety ◽  
Influence Line ◽  
Vehicle Load

Accurate calculation of the vehicle load is the foundation for the middle and small bridge safety. Longitudinal influence line and transverse distribution coefficient are used in traditional calculation method of vehicle load. This method brings a little big error because of the simplification. A new method based on influence surface is offered in this paper. The analysis results show that the new method can meet more accurate demand.

A New Method for the Generation of Tool Paths for Finishing Near Net Shape Components

2013 ◽  
Author(s):  
Edgar A. Mendoza López ◽  
Hugo I. Medellín Castillo ◽  
Dirk F. de Lange ◽  
Theo Lim
Keyword(s):  
Geometric Modeling ◽  
Tool Path ◽  
Cutting Tools ◽  
Approximation Error ◽  
Cnc Machining ◽  
New Method ◽  
End Mill ◽  
Tool Paths ◽  
Near Net Shape ◽  
Finish Cut

The CNC machining has been one of the most recurrent processes used for finishing NNS components. This paper presents a new method for the generation of tool paths for machining 3D NNS models. The proposed approach comprises two machining stages: rough cut and finish cut, and three types of cutting tools: ball-end mill, flat-end mill and fillet-end mill. The proposed tool path generation algorithm is based on: (1) approximation of the model surfaces by points using slice planes and visibility analysis, (2) accessibility analysis of the tool, (3) approximation error and tolerance evaluation, (4) collision analysis of tool and tool holder. The tools paths generated are exported as a CNC program. The implementation was carried out in C++ using the ACIS® geometric modeling kernel to support the required geometric operations. To prove the effectiveness of the system several models with variable geometric complexity were tested. The results have shown that the proposed system is effective and therefore can be used to generate the tool paths required for finishing 3D NNS components.

Research of the Chamfer Millers for the Gears

2011 ◽  
Vol 179-180 ◽  
pp. 960-966
Author(s):  
Hu Ran Liu
Keyword(s):  
Machine Tool ◽  
Product Quality ◽  
Tool Life ◽  
Calculation Method ◽  
Design Principle ◽  
New Method ◽  
Milling Machine ◽  
Batch Production ◽  
Machining Quality ◽  
The Past

In order to improve productivity and product quality and reduce cost, over the past many years, producers made great efforts to find the new method of chamfering. One of the methods is the chamfer milling cutter, on the milling machine tool. This method is suited for medium and small batch production. The tool life is long, the machining quality is stable. In this thesis, the principle of meshing between gear and the rake is applied. The chamfer miller design principle and calculation method is put forward.

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